Field of the Invention and Related Art Statement
This invention relates to an endoscope provided in the insertable section with a flexible part which can be made linear by an operation on the hand base side.
Recently there has come to be extensively used an endoscope whereby a body cavity interior can be observed and, as required, a treating instrument can be inserted to therapeutically treat the body cavity.
The endoscope has a curvable part formed by connecting curvable frames through shafts so that, when an angle wire fixed at the tip to the curvable part at the tip is pulled on the hand base side, the curvable part will be curved. Also, an insertable section flexible tube bendable in any direction is connected to the final frame of the curvable part at the rear end so as to be insertable into bent body cavity.
However, it is difficult or impossible in some case to insert such structure as is mentioned above into such turned and curved organ as the S-like colon part of the large intestine by making the organ linear.
Therefore, in the publication of Japanese utility model application laid open No. 22641/1989, a coil pipe fixed at the rear end within an operating section is fixed at the tip to the tip frame of a second curvable part consisting of curvable frames and shafts in the rear of a first curvable part to give some degree of stiffness to the second curvable part so that, as a result, the part of the second curvable part may be well along the body cavity wall and may help to insert the endoscope.
In the prior art example disclosed in the above mentioned Japanese utility model publication number 22641/1989, in the case of inserting the endoscope over the sharply curved S-like course within the body cavity, as shown in FIG. 1, in the bent part a, the curvable part 202 in the rear of the first curvable part 201 will be well along the body cavity wall and will not obstruct the insertion but, in the bent part b, the flexible tube 203 will not be well along the body cavity wall and will only push the body cavity wall in the direction indicated by the arrow c even if the endoscope is forcibly pushed and there have been defects that not only the endoscope can not be inserted but also a pain is given to the patient.